Protective face masks or respirators for the human face are well known. Persons wearing such respirators often have a need to communicate with one another, particularly in emergency situations. Such emergency situations include fires involving firefighters for whom effective communications with each other and with a command center are critical. Other examples of such emergency situations include military operations wherein military personnel must also communicate with each other and with a central command center.
Because users of these respirators, such as firefighters or military personnel, typically work in hostile environments, it is imperative that the mask remain on the user at all times while the user remains in that environment. Any voice communications systems associated with the mask must also not substantially interfere with the movement of the user. Thus, it is desirable when designing voice communications systems for face masks to eliminate unnecessary wires which might otherwise become entangled with the arms of the user or a stationary object and cause the mask to be pulled away from the face of the user.
A wireless communications apparatus for use in hazardous environments is shown, for example, in U.S. Pat. No. 4,885,796 to Loftus et al. The Loftus apparatus includes a face mask which covers the eyes, nose and mouth of the user. A relatively low power transmitter is located entirely within the mask for transmitting a short range signal carrying a communication from the user. A receiver carried on the user's person is tuned to receive the signal of the low powered transmitter and to provide an audio output. A relatively higher powered transceiver is also carried on the user's person. A voice actuated switch is responsive to the output of the receiver to switch the transceiver from a receiving mode to a transmitting mode. A cable connects the voice actuated switch and the transceiver to switch the transceiver between its receiving and transmitting operational modes, and to supply the output of the receiver as the audio input to the transceiver so that the user may communicate with remote receivers tuned to the frequency of the transceiver.
Positioning the transmitter entirely inside the mask as in the Loftus device, however, is less advantageous than locating the transmitter on the outside of the mask. For example, the addition of any foreign objects inside the mask poses a potential safety concern, as well as a comfort inconvenience for the user. Moreover, transmitters located on the inside of the mask are not as easily removable and adaptable to other masks. Ease of removability is an important feature because the mask is typically cleaned when the transmitter is detached from the mask. In addition, by placing the transmitter on the inside of the mask, the transmitter may not be removed while the user is wearing the mask.
Thus it is desirable to place the transmitter on the outside of the mask, to eliminate the disadvantages cited above. However, positioning the transmitter on the outside of the mask provides a technical challenge as the user's voice is further removed from the transmitter and therefore more difficult to detect and process. Accordingly, it is an object of the present invention to provide a wireless voice transmission system for a face mask for use in hostile environments, wherein the face mask is provided with a wireless transmitter mounted to and easily removable from the outside of the mask. It is a further object to provide a wireless two-way voice communications system which may be used in conjunction with or without a protective face mask.